Charge coupled device (CCD) serial storage registers having a straight channel are well-known in the art as disclosed in Sequin et al, Charge Coupled Devices, Academic Press, 1975, page 38, FIG. 3.8a. In such straight channel CCD devices, crossover of conductors or electrodes carrying different clock signals may allow pin holes in the insulating oxide layer to destroy device operation by electrical shorting between different conductors.
The prior art teaches using such straight channel CCD serial registers to store serial readout of data from CCD focal plane arrays. Such an arrangement is disclosed in Sequin et al, Charge Transfer Devices, Academic Press, 1975, page 179, FIG. 5.20. In such devices, charge packets generated by each of the plurality of photodetectors, are parallel-loaded into a single serial output register. At the interface between the detector output channels and the single serial register, each charge packet is transferred across a path having a width limited by the width of a single serial electrode of the CCD register, thereby limiting charge transfer speed and efficiency at this interface.
A charge coupled device having a meander channel is disclosed in Ohtsuki et al, "CCD With Meander Channel," Third International Conference on Technology and Applications of CCD's, 1976, pages 38-43. The Ohtsuki publication discloses a CCD having channel stops which define a meander channel in which charge transfer is controlled by two parallel linear electrodes disposed side-by-side over the meander channel and parallel to the channel. The electrodes are clocked by opposite phases of a two-phase clocking system. The disadvantage of such a device is that, if the electrodes overlap, they must be formed in different layers over the charge coupled device, so that they are mutually insulated. As a result, the two electrodes must be disposed at different heights over the charge flow channel, which creates an unsymmetrical surface potential distribution in the device. On the other hand, if the two linear electrodes are formed in the same conductive layer over the substrate, there must be an insulating gap between the two electrodes so that the two electrodes remain insulated from one another. As a result, no electrode directly overlies the gap, which causes instability in charge transfer under the gap.